SEQUENTIAL SAMPLING OF ADULT COCCINELLA SEPTEMPUNCTATA L. IN WHEAT FIELDS

1988 ◽  
Vol 120 (8-9) ◽  
pp. 773-778 ◽  
Author(s):  
G. Iperti ◽  
L. Lapchin ◽  
A. Ferran ◽  
J.-M. Rabasse ◽  
J.-P. Lyon
Keyword(s):  
Spatial Heterogeneity ◽  
Power Law ◽  
Sequential Sampling ◽  
Coccinella Septempunctata ◽  
Counting Method ◽  
Sampling Program ◽  
Taylor's Power Law ◽  
Mean And Variance ◽  
The Mean ◽  
The Relationship

AbstractA sequential sampling program was designed for Coccinella septempunctata L. adults in wheat fields, based on a rapid visual counting method. This program takes into account the spatial heterogeneity of coccinellids and the efficiency of the counting method. The relationship between the mean and variance of the numbers sampled was described by Taylor’s power law.

Sequential sampling plans for nematodes affecting sugarcane in Queensland

1990 ◽  
Vol 41 (2) ◽  
pp. 351 ◽  
Author(s):  
PG Allsopp
Keyword(s):  
Power Law ◽  
Negative Binomial ◽  
Sequential Sampling ◽  
Taylor’S Power Law ◽  
Functional Relationships ◽  
Precision Level ◽  
Taylor's Power Law ◽  
Mean And Variance ◽  
Population Counts ◽  
The Relationship

The dispersion characteristics of root-lesion, root-knot, spiral, stubby-root, stunt and ring nematodes in soil, and root-lesion, root-knot and spiral nematodes in roots in sugarcane fields, were determined in studies in southern Queensland. The Poisson distribution, negative binomial distribution, Iwao's regression model and Taylor's power law analysis were used to determine the relationship between mean and variance of nematode counts. All methods showed that nematodes were aggregated (Iwao's G 1.12-1.65, Taylor's b 1.10-1.76). In general, Taylor's power law gave better fit compared with the other models (R2>0.61). Relationships to determine sample sizes for fixed levels of precision and fixed-precision-level stop lines for sequential sampling were developed for all species. There were functional relationships between variance and mean of untransformed population counts for all species, but suitable transformations eliminated significant correlations in most cases.

Spatial patterns and sequential sampling plans for melolonthine larvae (Coleoptera: Scarabaeidae) in southern Queensland sugarcane

1989 ◽  
Vol 79 (2) ◽  
pp. 251-258 ◽  
Author(s):  
P. G. Allsopp ◽  
R. M. Bull
Keyword(s):  
Power Law ◽  
Negative Binomial ◽  
Sequential Sampling ◽  
The Other ◽  
Taylor’S Power Law ◽  
Functional Relationships ◽  
Taylor's Power Law ◽  
Mean And Variance ◽  
Population Dispersion ◽  
Population Counts

AbstractThe within-row dispersion characteristics of larvae of Antitrogus mussoni (Blackburn), A. parvulus Britton, Lepidiota crinita Brenske, L. negatoria Blackburn, L. noxia Britton and L. picticollis Lea in sugarcane were determined in studies in southern Queensland, Australia. The Poisson distribution, negative binomial distribution, Iwao's regression model and Taylor's power law analysis were used to determine the relationship between mean and variance of larval counts. All methods examined showed that the larvae were slightly aggregated. Taylor's power law generally gave equivalent or better fits to the population dispersion compared with the other models. The power law relationship for L. picticollis differed from those of the other five species, and a common relationship for those five species was determined. Relationships to determine sample sizes for fixed levels of precision and fixed-precision-level stop lines for sequential sampling were developed for both L. picticollis and the other five species. There were functional relationships between the variance and mean of untransformed population counts for all species, and the suitability of transformation functions is discussed.

Dispersion patterns and sequential sampling plans for Megalurothrips sjostedti (Trybom) (Thysanoptera: Thripidae) in cowpeas

1987 ◽  
Vol 77 (3) ◽  
pp. 441-449 ◽  
Author(s):  
A. B. Salifu ◽  
C. J. Hodgson
Keyword(s):  
Power Law ◽  
Negative Binomial ◽  
Sequential Sampling ◽  
Megalurothrips Sjostedti ◽  
Taylor’S Power Law ◽  
Regression Procedure ◽  
Taylor's Power Law ◽  
Mean And Variance ◽  
Population Dispersion ◽  
Population Counts

AbstractThe within-plant dispersion characteristics of Megalurothrips sjostedti (Trybom) on cowpeas were determined in studies in Nigeria. Iwao's regression procedure and Taylor's power law analysis were used to determine the relationship between the mean and variance of thrips counts. Both methods showed that adult thrips were randomly distributed within cowpea plants at initial low populations. At later high densities, Iwao's method provided a better fit of the population dispersion of larvae and adults and showed that both were aggregated. The negative binomial best described this aggregation at high population densities. Sequential count plans suitable for pest management surveys were developed using critical stop lines derived from Iwao's regression procedure and Taylor's power law, but the latter was found to require less effort to achieve the same level of precision. There was a functional relationship between the variance and mean of untransformed population counts, and the suitability of transformation functions is discussed.

scholarly journals GENETIC VARIABILITY MAINTAINED BY MUTATION AND OVERDOMINANT SELECTION IN FINITE POPULATIONS

Genetics ◽  
1981 ◽  
Vol 98 (2) ◽  
pp. 441-459 ◽  
Author(s):  
Takeo Maruyama ◽  
Masatoshi Nei
Keyword(s):  
Mutation Rate ◽  
Allozyme Polymorphism ◽  
Random Genetic Drift ◽  
Effective Population ◽  
Mathematical Properties ◽  
Overdominant Selection ◽  
Mean And Variance ◽  
The Mean ◽  
Neutral Mutations ◽  
The Relationship

ABSTRACT Mathematical properties of the overdominance model with mutation and random genetic drift are studied by using the method of stochastic differential equations (Itô and McKean 1974). It is shown that overdominant selection is very powerful in increasing the mean heterozygosity as compared with neutral mutations, and if 2Ns (N = effective population size; s = selective disadvantage for homozygotes) is larger than 10, a very low mutation rate is sufficient to explain the observed level of allozyme polymorphism. The distribution of heterozygosity for overdominant genes is considerably different from that of neutral mutations, and if the ratio of selection coefficient (s) to mutation rate (ν) is large and the mean heterozygosity (h) is lower than 0.2, single-locus heterozygosity is either approximately 0 or 0.5. If h increases further, however, heterozygosity shows a multiple-peak distribution. Reflecting this type of distribution, the relationship between the mean and variance of heterozygosity is considerably different from that for neutral genes. When s/v is large, the proportion of polymorphic loci increases approximately linearly with mean heterozygosity. The distribution of allele frequencies is also drastically different from that of neutral genes, and generally shows a peak at the intermediate gene frequency. Implications of these results on the maintenance of allozyme polymorphism are discussed.

Spatial distribution and sequential sampling of Nysius spp. (Hemiptera: Lygaeidae) on sunflowers

1988 ◽  
Vol 28 (2) ◽  
pp. 279 ◽  
Author(s):  
PG Allsopp ◽  
S Iwao ◽  
LR Taylor
Keyword(s):  
Power Law ◽  
Negative Binomial ◽  
Sequential Sampling ◽  
Binomial Model ◽  
Sequential Decision ◽  
Taylor’S Power Law ◽  
Crop Development ◽  
Precision Level ◽  
Taylor's Power Law ◽  
Mixed Populations

Counts of adults of mixed populations of Nysius vinitor Bergroth and N. clevelandensis Evans on preflowering and postflowering sunflowers did not conform to the Poisson distribution because of overdispersion. Preflowering samples did not conform to the negative binomial model, but postflowering samples did with a common k of 3.78. Both sets of samples fitted significantly (P<0.01) Iwao's patchiness regression and Taylor's power law, but with significantly (P<0.01) different intercepts and slopes, respectively. Relationships to determine sample sizes for fixed levels of precision and fixed-precision-level stop lines are developed for both stages of crop development using Taylor's power law. Sequential decision plans based on Iwao's regression are developed for use in the management of Nysius spp. on preflowering and postflowering sunflowers.

Taylor’s power law and fixed-precision sampling: application to abundance of fish sampled by gillnets in an African lake

2017 ◽  
Vol 74 (1) ◽  
pp. 87-100 ◽  
Author(s):  
Meng Xu ◽  
Jeppe Kolding ◽  
Joel E. Cohen
Keyword(s):  
Power Law ◽  
Fish Assemblage ◽  
Mesh Size ◽  
Stock Management ◽  
Taylor’S Power Law ◽  
Scaling Relationship ◽  
Temporal Variance ◽  
Taylor's Power Law ◽  
Power Law Function ◽  
The Mean

Taylor’s power law (TPL) describes the variance of population abundance as a power-law function of the mean abundance for a single or a group of species. Using consistently sampled long-term (1958–2001) multimesh capture data of Lake Kariba in Africa, we showed that TPL robustly described the relationship between the temporal mean and the temporal variance of the captured fish assemblage abundance (regardless of species), separately when abundance was measured by numbers of individuals and by aggregate weight. The strong correlation between the mean of abundance and the variance of abundance was not altered after adding other abiotic or biotic variables into the TPL model. We analytically connected the parameters of TPL when abundance was measured separately by the aggregate weight and by the aggregate number, using a weight–number scaling relationship. We utilized TPL to find the number of samples required for fixed-precision sampling and compared the number of samples when sampling was performed with a single gillnet mesh size and with multiple mesh sizes. These results facilitate optimizing the sampling design to estimate fish assemblage abundance with specified precision, as needed in stock management and conservation.

SAMPLING PLANS FOR ESTIMATING ACHENE DAMAGE BY THE RED SUNFLOWER SEED WEEVIL (COLEOPTERA: CURCULIONIDAE)

1995 ◽  
Vol 127 (1) ◽  
pp. 7-14 ◽  
Author(s):  
Chengwang Peng ◽  
Gary J. Brewer
Keyword(s):  
Sample Size ◽  
Distribution Pattern ◽  
Power Law ◽  
Sunflower Seed ◽  
Management Strategies ◽  
Economic Injury Level ◽  
Taylor’S Power Law ◽  
Precision Level ◽  
Taylor's Power Law ◽  
The Mean

AbstractA sampling plan for the estimation of the number of achenes damaged by the red sunflower seed weevil, Smicronyx fulvus LeConte, is useful in evaluating the efficiency of weevil management strategies. The objective of this study was to determine the distribution pattern of the damaged achenes that would allow the development of a fixed-sample-size plan for estimation of the damaged achenes. Taylor’s power law and Iwao’s patchiness regression were used to analyze the distribution pattern of the damaged achenes. Slopes from both models were >1, indicating an aggregated spatial pattern. The intercepts and slopes from both models were used to calculate the minimal mean number of damaged achenes per sunflower head that can be estimated for a given sample size and precision level. If the mean number of damaged achenes per head is low (<20), the plan developed using the parameters of Taylor’s power law requires significantly more samples than the plan using the parameters of Iwao’s patchiness regression to estimate the same density of damaged achenes. If the mean number of damaged achenes per head is high (>30), the two plans give similar results. If both low and high damage situations are considered, Taylor’s plan is preferred to Iwao’s plan. At the 0.10 precision level, Taylor’s plan requires approximately 40 samples (heads) to estimate a mean of about 200 damaged achenes per head (≈ current economic injury level).

Influence of Lake pH and Macrograzers on the Distribution and Abundance of Nuisance Metaphytic Algae in Ontario, Canada

1992 ◽  
Vol 49 (1) ◽  
pp. 185-195 ◽  
Author(s):  
Robert L. France ◽  
Pamela M. Welbourn
Keyword(s):  
Sequential Sampling ◽  
Low Ph ◽  
Shallow Depth ◽  
Softwater Lakes ◽  
Sampling Program ◽  
Managerial Implications ◽  
The Relationship

Thirty-six softwater lakes in central Ontario were sampled during 1988 to determine the relationship between metaphytic Zygnematacean algae and lake pH and the degree of complementarity between the presence of metaphyton and that of crayfish and tadpoles. A stratified sequential sampling program was developed to quantitatively measure and to objectively categorize average metaphyton abundance for each lake. A significantly greater proportion of lakes below pH 6 were found to contain extensive accumulations of metaphyton compared with lakes above pH 6. Lake pH and alkalinity were significantly correlated with metaphyton abundance. Macro-grazer density did not significantly influence the presence or absence of metaphyton, but reduced metaphyton abundance in those lakes which, because of their low pH or shallow depth, were predisposed to its accumulation. Managerial implications regarding the stocking of crayfish or tadpoles to limit the nuisance proliferation of metaphyton, and the importance of predaceous fishes in structuring this interaction, are discussed.

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